On a candy production line, 3% of bags are overfilled. An employee randomly selects 100 bags and finds that 5% are overfilled. A second employees takes another random sample of 250 bags and finds that 2% are overfilled. Which of the following explains why there is a difference between the two percentages? a. Random error; the numbers were different due to variability inherent in sampling.
b. The samples were not random samples.
c. Both samples suffered from non-response bias.
d. The sample sizes were both too small, which is why they both obtained figures different than 3%